/*
 * MD5Encryption.cpp
 *
 *  Created on: Nov 26, 2014
 *      Author: Mason
 */

/* F, G, H and I are basic MD5 functions */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4 */
/* Rotation is separate from addition to prevent recomputation */
#define FF(a, b, c, d, x, s, ac) \
  {(a) += F ((b), (c), (d)) + (x) + (unsigned long)(ac); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) \
  {(a) += G ((b), (c), (d)) + (x) + (unsigned long)(ac); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) \
  {(a) += H ((b), (c), (d)) + (x) + (unsigned long)(ac); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) \
  {(a) += I ((b), (c), (d)) + (x) + (unsigned long)(ac); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

#include <cstring>
#include <string>
#include <boost/format.hpp>

#include "GreenLeaf/GLUtils/MD5Encryption.h"

namespace GreenLeaf {
namespace GLUtils {

static unsigned char PADDING[64] = {
    0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

MD5Encryption& MD5Encryption::instance()
{
    static MD5Encryption _gInstance;
    return _gInstance;
}

//==================================
// ¿ªÊŒMD5ŒÓÃÜ
//==================================
void MD5Encryption::digest_md5(unsigned char* buffer, int buffer_len, unsigned char* digest)
{
    MD5_CTX ctx;
    MD5Init(&ctx);
    MD5Update(&ctx, buffer, buffer_len);
    MD5Final(&ctx);
    memcpy(digest, ctx.digest, sizeof(ctx.digest));
}

/* The routine MD5Init initializes the message-digest context
   mdContext. All fields are set to zero.
 */
void MD5Encryption::MD5Init(MD5_CTX *mdContext)
{
    mdContext->i[0] = mdContext->i[1] = (unsigned long)0;

    /* Load magic initialization constants.
    */
    mdContext->buf[0] = (unsigned long)0x67452301L;
    mdContext->buf[1] = (unsigned long)0xefcdab89L;
    mdContext->buf[2] = (unsigned long)0x98badcfeL;
    mdContext->buf[3] = (unsigned long)0x10325476L;
}

/*
The routine MD5Update updates the message-digest context to
account for the presence of each of the characters
inBuf[0..inLen-1]
in the message whose digest is being computed.
*/

void MD5Encryption::MD5Update(register MD5_CTX *mdContext, unsigned char *inBuf, unsigned int inLen)
{
    register int i, ii;
    int mdi;
    unsigned long in[16];

    /* compute number of bytes mod 64 */
    mdi = (int)((mdContext->i[0] >> 3) & 0x3F);

    /* update number of bits */
    if ((mdContext->i[0] + ((unsigned long)inLen << 3)) < mdContext->i[0]) {
        mdContext->i[1]++;
    }
    mdContext->i[0] += ((unsigned long)inLen << 3);
    mdContext->i[1] += ((unsigned long)inLen >> 29);

    while (inLen--) {
        /* add new character to buffer, increment mdi */
        mdContext->in[mdi++] = *inBuf++;

        /* transform if necessary */
        if (mdi == 0x40) {
            for (i = 0, ii = 0; i < 16; i++, ii += 4) {
                in[i] = (((unsigned long)mdContext->in[ii+3]) << 24) |
                        (((unsigned long)mdContext->in[ii+2]) << 16) |
                        (((unsigned long)mdContext->in[ii+1]) << 8) |
                        ((unsigned long)mdContext->in[ii]);
            }

            this->transform(mdContext->buf, in);
            mdi = 0;
        }
    }
}

/*
The routine MD5Final terminates the message-digest computation and
ends with the desired message digest in mdContext->digest[0...15].
*/
void MD5Encryption::MD5Final(MD5_CTX *mdContext)
{
    unsigned long in[16];
    int mdi;
    unsigned int i, ii;
    unsigned int padLen;

    /* save number of bits */
    in[14] = mdContext->i[0];
    in[15] = mdContext->i[1];

    /* compute number of bytes mod 64 */
    mdi = (int)((mdContext->i[0] >> 3) & 0x3F);

    /* pad out to 56 mod 64 */
    padLen = (mdi < 56) ? (56 - mdi) : (120 - mdi);
    MD5Update(mdContext, PADDING, padLen);

    /* append length in bits and transform */
    for (i = 0, ii = 0; i < 14; i++, ii += 4) {
        in[i] = (((unsigned long)mdContext->in[ii+3]) << 24) |
                (((unsigned long)mdContext->in[ii+2]) << 16) |
                (((unsigned long)mdContext->in[ii+1]) << 8) |
                ((unsigned long)mdContext->in[ii]);
    }

    this->transform(mdContext->buf, in);

    /* store buffer in digest */
    std::string strTemp;

    for (i = 0, ii = 0; i < 4; i++, ii += 8) {
        strTemp = boost::str(boost::format("%02x") % (mdContext->buf[i] & 0xFF));
        mdContext->digest[ii]   = (unsigned char)strTemp.at(0);
        mdContext->digest[ii+1] = (unsigned char)strTemp.at(1);

        strTemp = boost::str(boost::format("%02x") % ((mdContext->buf[i] >> 8) & 0xFF));
        mdContext->digest[ii+2] = (unsigned char)strTemp.at(0);
        mdContext->digest[ii+3] = (unsigned char)strTemp.at(1);

        strTemp = boost::str(boost::format("%02x") % ((mdContext->buf[i] >> 16) & 0xFF));
        mdContext->digest[ii+4] = (unsigned char)strTemp.at(0);
        mdContext->digest[ii+5] = (unsigned char)strTemp.at(1);

        strTemp = boost::str(boost::format("%02x") % ((mdContext->buf[i] >> 24) & 0xFF));
        mdContext->digest[ii+6] = (unsigned char)strTemp.at(0);
        mdContext->digest[ii+7] = (unsigned char)strTemp.at(1);
    }
}

/*
Basic MD5 step. Transforms buf based on in.  Note that if the
Mysterious Constants are arranged backwards in little-endian order
and decrypted with the DES they produce OCCULT MESSAGES!
*/
void MD5Encryption::transform(register unsigned long *buf, register unsigned long *in)
{
    register unsigned long a = buf[0], b = buf[1], c = buf[2], d = buf[3];

    /* Round 1 */
    FF ( a, b, c, d, in[ 0], S11, 0xD76AA478L); /* 1 */
    FF ( d, a, b, c, in[ 1], S12, 0xE8C7B756L); /* 2 */
    FF ( c, d, a, b, in[ 2], S13, 0x242070DBL); /* 3 */
    FF ( b, c, d, a, in[ 3], S14, 0xC1BDCEEEL); /* 4 */
    FF ( a, b, c, d, in[ 4], S11, 0xF57C0FAFL); /* 5 */
    FF ( d, a, b, c, in[ 5], S12, 0x4787C62AL); /* 6 */
    FF ( c, d, a, b, in[ 6], S13, 0xA8304613L); /* 7 */
    FF ( b, c, d, a, in[ 7], S14, 0xFD469501L); /* 8 */
    FF ( a, b, c, d, in[ 8], S11, 0x698098D8L); /* 9 */
    FF ( d, a, b, c, in[ 9], S12, 0x8B44F7AFL); /* 10 */
    FF ( c, d, a, b, in[10], S13, 0xFFFF5BB1L); /* 11 */
    FF ( b, c, d, a, in[11], S14, 0x895CD7BEL); /* 12 */
    FF ( a, b, c, d, in[12], S11, 0x6B901122L); /* 13 */
    FF ( d, a, b, c, in[13], S12, 0xFD987193L); /* 14 */
    FF ( c, d, a, b, in[14], S13, 0xA679438EL); /* 15 */
    FF ( b, c, d, a, in[15], S14, 0x49B40821L); /* 16 */

    /* Round 2 */
    GG ( a, b, c, d, in[ 1], S21, 0xF61E2562L); /* 17 */
    GG ( d, a, b, c, in[ 6], S22, 0xC040B340L); /* 18 */
    GG ( c, d, a, b, in[11], S23, 0x265E5A51L); /* 19 */
    GG ( b, c, d, a, in[ 0], S24, 0xE9B6C7AAL); /* 20 */
    GG ( a, b, c, d, in[ 5], S21, 0xD62F105DL); /* 21 */
    GG ( d, a, b, c, in[10], S22, 0x02441453L); /* 22 */
    GG ( c, d, a, b, in[15], S23, 0xD8A1E681L); /* 23 */
    GG ( b, c, d, a, in[ 4], S24, 0xE7D3FBC8L); /* 24 */
    GG ( a, b, c, d, in[ 9], S21, 0x21E1CDE6L); /* 25 */
    GG ( d, a, b, c, in[14], S22, 0xC33707D6L); /* 26 */
    GG ( c, d, a, b, in[ 3], S23, 0xF4D50D87L); /* 27 */
    GG ( b, c, d, a, in[ 8], S24, 0x455A14EDL); /* 28 */
    GG ( a, b, c, d, in[13], S21, 0xA9E3E905L); /* 29 */
    GG ( d, a, b, c, in[ 2], S22, 0xFCEFA3F8L); /* 30 */
    GG ( c, d, a, b, in[ 7], S23, 0x676F02D9L); /* 31 */
    GG ( b, c, d, a, in[12], S24, 0x8D2A4C8AL); /* 32 */

    /* Round 3 */
    HH ( a, b, c, d, in[ 5], S31, 0xFFFA3942L); /* 33 */
    HH ( d, a, b, c, in[ 8], S32, 0x8771F681L); /* 34 */
    HH ( c, d, a, b, in[11], S33, 0x6D9D6122L); /* 35 */
    HH ( b, c, d, a, in[14], S34, 0xFDE5380CL); /* 36 */
    HH ( a, b, c, d, in[ 1], S31, 0xA4BEEA44L); /* 37 */
    HH ( d, a, b, c, in[ 4], S32, 0x4BDECFA9L); /* 38 */
    HH ( c, d, a, b, in[ 7], S33, 0xF6BB4B60L); /* 39 */
    HH ( b, c, d, a, in[10], S34, 0xBEBFBC70L); /* 40 */
    HH ( a, b, c, d, in[13], S31, 0x289B7EC6L); /* 41 */
    HH ( d, a, b, c, in[ 0], S32, 0xEAA127FAL); /* 42 */
    HH ( c, d, a, b, in[ 3], S33, 0xD4EF3085L); /* 43 */
    HH ( b, c, d, a, in[ 6], S34, 0x04881D05L); /* 44 */
    HH ( a, b, c, d, in[ 9], S31, 0xD9D4D039L); /* 45 */
    HH ( d, a, b, c, in[12], S32, 0xE6DB99E5L); /* 46 */
    HH ( c, d, a, b, in[15], S33, 0x1FA27CF8L); /* 47 */
    HH ( b, c, d, a, in[ 2], S34, 0xC4AC5665L); /* 48 */

    /* Round 4 */
    II ( a, b, c, d, in[ 0], S41, 0xF4292244L); /* 49 */
    II ( d, a, b, c, in[ 7], S42, 0x432AFF97L); /* 50 */
    II ( c, d, a, b, in[14], S43, 0xAB9423A7L); /* 51 */
    II ( b, c, d, a, in[ 5], S44, 0xFC93A039L); /* 52 */
    II ( a, b, c, d, in[12], S41, 0x655B59C3L); /* 53 */
    II ( d, a, b, c, in[ 3], S42, 0x8F0CCC92L); /* 54 */
    II ( c, d, a, b, in[10], S43, 0xFFEFF47DL); /* 55 */
    II ( b, c, d, a, in[ 1], S44, 0x85845DD1L); /* 56 */
    II ( a, b, c, d, in[ 8], S41, 0x6FA87E4FL); /* 57 */
    II ( d, a, b, c, in[15], S42, 0xFE2CE6E0L); /* 58 */
    II ( c, d, a, b, in[ 6], S43, 0xA3014314L); /* 59 */
    II ( b, c, d, a, in[13], S44, 0x4E0811A1L); /* 60 */
    II ( a, b, c, d, in[ 4], S41, 0xF7537E82L); /* 61 */
    II ( d, a, b, c, in[11], S42, 0xBD3AF235L); /* 62 */
    II ( c, d, a, b, in[ 2], S43, 0x2AD7D2BBL); /* 63 */
    II ( b, c, d, a, in[ 9], S44, 0xEB86D391L); /* 64 */

    buf[0] += a;
    buf[1] += b;
    buf[2] += c;
    buf[3] += d;
}

} } // GreenLeaf::GLUtils

